Antitubercular chemotherapeutic drugs presently used all over the world comprise primarily of synthetic drugs, e.g., isoniazid (i.e., isonicotinic acid hydrazide), used singly or in combination with sodium PAS (sodium para amino salicylate), ISONEX (isoniazid), ERBAZIDE (calcium methanesulfonate of isoniazid), cyclocerine, morphazinamide hydrochloride, rifampicin, MYAMBUTOL (ethambutol), sparfloxicin, etc. which were developed subsequent to the synthesis of the antibiotic streptomycin.
While there are cures for tuberculosis by using the above mentioned drugs along with the BCG vaccination, several drawbacks are noticed, especially in terms of side effects of such drugs, the requirement of prolonged intake/duration of therapy. Another problem observed is that even after treatment, some mycobacterium continue to reside in the subject. It is therefore imperative to create alternatives to the above class of drugs so that either the dosage or the intake duration is reduced or the problem of resistance to the drugs is obviated.
Reference is made to K. Usha et al., who in a paper entitled “Antitubercular potential of selected plant materials” in Journal of Medicinal and Aromatic Plant Sciences, 22/4A-23/1A, 182-184 (Eng.) (2000-2001), describe the antitubercular potential of the plants viz., neem, tulsi, garlic, ginger and adhatoda, which were tested by in vitro culture using 100 mL of aqueous puree (50% w/v) of plant material added to sputum and then inoculated in to LJ medium. All the plant extracts arrested the growth of Mycobacterium tuberculosis, which was ascribed to enzymic and nonenzymic antioxidants such as catalase, peroxidase, total carotene, ascorbic acid, tocopherol, and polyphenols thus preventing tissue damage by ROS (reactive oxygen species). Besides the large quantity of potion that needs to be applied, it is unclear as to the extent of inhibition and the MIC of the potion.
Reference is made to N. Lall et al. in a paper entitled “In vitro inhibition of drug-resistant and drug-sensitive strains of Mycobacterium tuberculosis by ethnobotanically selected South African plants” in Journal of Ethnopharmacology, 66, 347-354 (1999), which describes the preliminary screening of 20 South African medicinal plant extracts against a drug-sensitive strain, H37Rv, of Mycobacterium tuberculosis by agar plate method (Middlebrook and Cohn, 1958). Herein the author ascribes 14 out of 20 acetone extracts showing inhibitory activity at concentration of 500 μg/ml whereas acetone as well water extracts of plant species namely Cryptocarya latifolia, Euclea natalensis, Helichrysum melanacme, Nidorella anomala and Thymus vulgaris indicated MIC of 100 μg/ml against H37Rv strain by radiometric method.
Reference is also made to C. L. Cantrell et al. in a review article entitled “Antimycobacterial plant terpenoids” in Journal of Planta Medica, 67(8), 685-694 (Eng.) (2001), which covers recent report on plant-derived terpenoids that have demonstrated moderate to high activity in in vitro bioassays against M. tuberculosis. In this review, mono-, sesqui-, di- and triterpenes & sterols, their structural analogue and semi synthetic derivatives have been discussed with particular emphasis on the structural features essential for antimycobacterial activity.
Reference is made to Ma, Junrui in a patent entitled “Compositions containing herbal medicine for pulmonary tuberculosis” No. CN 1265315 A 6 Sep. 2000, 4 pp. (Chinese) (2001), which contains the different forms of composition (aerosol, inhalant, tablet, capsule, powder, oral concentrate and liquid) for treating pulmonary tuberculosis composed of Taraktogenos, Coptis, Stemona, Cordyceps, Scutellaria, Lonicera japonica, Forsythia vahl, Herba violae, Anemarrhena, Salvia miltiorrhiza, Fructus mume, Ginkgo biloba, Anacamptis pyoamidalis Richard, Polygonatum, Glycyrrhiza, Polygonum multiflorum thunb, Brunella vulgaris, Cirsium japonicum, leaf of Thuja orientalis, Sguisorba officinalis, Heracleum, common Andrographis, Houttuynia, herba artemisiae and Magnolia officinalis. However the drawback here is the use of multiple herbs for the purpose of elucidating the positive gains of plant against mycobacterium tuberculosis and without referring to MIC level either of individual herb or collectively of the combination.
Reference is made to a paper titled “Preliminary antimicrobial screening four South African Asteraceae species” by F. Salie et al. in Journal of Ethanopharmacology, 52, 27-33 (1996) wherein the author has investigated the flora of the Western Cape—a part of Cape Floral kingdom in South Africa. The author ascribes the efficacy of four Asteraceae species (Arctopis auriculanta, Eriocephalus africanus L., Felicia erigeroides DC. and Helichrysum crispum (L.) D. Don.) exhibiting selective anti-microbial activity to various degree for Mycobacterium smegmatis. Identifying the 8500 μg/ml of MIC in leaves of Arctopis auriculanta. The drawback of the invention is the very high MIC value. Reference is also made to Internet website benefits@coqui.net on Salicornia plant, where use of Salicornia plant as a source of edible oil and use of dried crushed stems as fuel briquettes or particleboard are reported. However, there is no mention of bioactivity of the plant.
Reference is also made to U.S. patent application Ser. No. 10/106,334 dt. 26th Mar. 2002 by P. K. Ghosh et al. wherein a vegetable salt preparation from residual dry matter after removal of seeds using halophyte has been described to maximize value derived from the plant. However this application does not provide any use of the plant for drug/medicinal purpose.
Reference is made to Wealth of India, vol. IX RH-SO which documents various bioresources of India and application thereof has listed Salicornia Linn. and its taxonomy beside use of the species as fodder. The plant is also listed in Flora of India by Hooker (1889), However no mention is made in both documents on any kind of bioactivity associated with Salicornia. 